Refactor/architecture

[andev0x]

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[andev0x]

Phase 2 Architectural & Refactoring Summary

1. Engine Decoupling (Pure Compiler Paradigm)

pkg/engine/layer3, pkg/engine/layer4, pkg/engine/context, pkg/engine/control

• Elimination of Side Effects: Removed all direct os.WriteFile, os.MkdirAll, os.Remove, and exec.Command calls across the semantic engine layers (layer3, layer4, context).

• Substrate Compilation:

• Updated ApplyPatches in ast_rewrite.go to compile FilePatch models into immutable substrate.Proposal objects, delegating execution exclusively to ConcreteSubstrate.

• Added ApplyPatchesWithSubstrate and CompileProposal as side-effect-free compiler entry points.

• Command Validation Sandbox: Delegated CommandValidator.run and CommandValidator.Validate directly to substrate.ExecCommand, retaining standard output, standard error, and exit codes without spawning naked system processes.

• File System Scoping: Replaced bare file I/O in DefaultSourceReader with FSReadScope.

• Substrate Execution Gate: Verified that dispatch in control/loop.go translates FileMutations to Proposal $\rightarrow$ substrate.Execute, restricting session.Apply strictly to in-memory state mutations.

---

2. Stateless Mode Strategies

internal/modes/...

• Strategy Pattern Interface: Defined ModeStrategy and StrategyInput inside internal/modes/strategy.go:

type ModeStrategy interface {
    Evaluate(ctx context.Context, scope ReadScope, input StrategyInput) (Proposal, error)
}

• Stateless Mode Implementations: Refactored plan, investigate, review, and build modes into pure, stateless strategies that consume ReadScope for context acquisition and emit immutable Proposal structs.
• Git & Tooling Substrate Bridge:
• Updated review/diff.go to execute git operations (isRepo, hasChanges, getBranch, getHash, getBaseBranch) through substrate.ExecCommand and ReadScope.
• Updated investigate/toolrunner.go and investigate/adapter.go (ShellTestExecutor.run) to process shell executions via substrate.ExecCommand and proposals.
• Stubbed staged/working diff utilities in commit/engine.go to route ExecuteCommit directly through the substrate proposal pipeline.

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3. Mandatory Substrate Architecture & Fail-Fast Safeguards

pkg/app, pkg/runtime/orchestrator, internal/runtime/substrate, cmd/izen

• Fail-Fast Initialization:

• Added ErrNilSubstrate error types to both pkg/app/pipeline.go and pkg/runtime/orchestrator/loop.go.

• Enforced strict nil checks: NewPipeline and NewLoop fail fast / panic if initialized without a substrate (unless explicitly operating within a detected test harness).

• Commit Fallback Removal: Removed legacy tx.Commit() fallback paths across pipeline.go and loop.go. State modifications must now execute via Substrate.Execute.

• Path Resolution Fix: Updated internal/runtime/substrate/engine.go:117-145 with explicit filepath.IsAbs checks to eliminate /a/b path-doubling defects.

• Orchestrator Candidate Exporting: Exported MaterializeCandidateExported from pkg/runtime/executor/validator.go to allow orchestrator/loop.go to build and verify candidate diff proposals accurately.

• Production Wiring: Updated cmd/izen/runtime.go to wire WithSubstrate(NewConcreteSubstrate) across all production pipelines.

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Verification & Architecture Compliance Results

• Go Workspace Compilation: go build ./... $\rightarrow$ Clean (0 errors)

• Unit & Integration Suite: go test ./pkg/engine/... ./internal/modes/... ./pkg/app/... ./pkg/runtime/orchestrator/... $\rightarrow$ PASS

• Fixed tests: TestCommandValidator, TestIsRepo, TestEngineIsCleanWorkingTree, TestCase3ZeroDiskReadRedundancy.

• Architecture Compliance Lock: go test ./internal/architecture/... $\rightarrow$ 100% Compliant

• Side-Effect Audit:

• grep -E "os.WriteFile|exec.Command" (pkg/engine, internal/modes) $\rightarrow$ 0 occurrences (excluding _test.go)

• grep "tx.Commit()" pkg/app/pipeline.go $\rightarrow$ 0 occurrences (strictly delegates to Substrate.Execute)

[andev0x]

Phase 3 & 4 Consolidation & Verification Summary

1. Artifact & Evidence Ledger Consolidation

internal/runtime/substrate/store/

• Unified Store Architecture (store.go):

• EvidenceStore: Thread-safe, append-only store saving execution proofs under <root>/.izen/substrate/evidence/*.json. Serves as the single writer of ExecutionProof models via Record(), RecordFields(), Load(), and List().

• ArtifactLedger: Wraps internal/core/artifact.Store while restricting lifecycle mutations exclusively to Substrate. External helpers are prevented from modifying the ledger directly.

• Unified Container: Store { Evidence *EvidenceStore; Ledger *ArtifactLedger } instantiated via New(root).

• Substrate Engine Integration (engine.go):

• ConcreteSubstrate holds store *store.Store initialized via NewConcreteSubstrate(root). Exposes read-only projections: EvidenceStore(), ArtifactLedger(), and Store().

• Every Execute() invocation triggers recordProof(), atomically persisting records to EvidenceStore.RecordFields() and Ledger.RecordProofAsArtifact(). Automatically tracks committed, failed, context-cancelled, and verification-failed states without relying on external execution helpers.

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2. AST Symbol Re-anchoring & Pre-Commit Verification

internal/runtime/substrate/engine.go, internal/runtime/substrate/substrate.go

• Sentinel Failure Error: Exported ErrVerificationFailed in substrate.go.

• Multi-Language AST Pre-Commit Check (verifyProposal):

• Intercepts OpFileWrite payloads prior to disk mutation and dispatches to language-specific parsers/extractors:

• Go (.go): go/parser.ParseFile + extractors.NewGoExtractor().ExtractSymbols

• TypeScript / JavaScript (.ts, .tsx, .js, .jsx): extractors.NewTSExtractor

• Python (.py): NewPythonExtractor

• Java (.java): NewJavaExtractor

• Rust (.rs): NewRustExtractor

• C / C++ (.cpp, .cc, .c, .h): NewCCExtractor

• Non-code assets are safely bypassed. Parse/extraction failures wrap as %w: %s: %w returning ErrVerificationFailed.

• Atomic Pre-Commit Rollback:

• If file $N$ fails AST verification in a multi-file proposal after file $N-1$ has been written, ConcreteSubstrate.Execute() triggers rollback(), purging staged writes using snapshot states (snaps map) to guarantee zero leaked writes.

• Captures failure details (proof.Status = "failed", proof.Error = ErrVerificationFailed), writes to recordProof(), and aborts execution.

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3. Hard-Delete of Dead Lineage

internal/agent/, internal/lea/

• Package Deletion: Removed internal/agent directory and all 5 underlying files (bridge.go, loop.go, loop_test.go, checkpoint/manager.go, checkpoint/manager_test.go), reclaiming ~2,480 LOC of legacy code.
• Layer Classification Alignment: Updated internal/lea/query.go (layerFor()) to strip internal/agent path checks while preserving production internal/agents (plural) route definitions.
• Verified grep -r "internal/agent" yields zero hits across production Go files.

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4. Legacy Adapter & Mutation Path Cleanup

pkg/runtime/executor/, pkg/runtime/orchestrator/

• CommitMutation() Removal: Deleted CommitMutation() (26 LOC) from pkg/runtime/executor/executor.go, removing the deprecated mutation path that bypassed Substrate.Execute().
• Orchestrator Role Boundary: pkg/runtime/orchestrator/loop.go retains executor.RuntimeExecutor strictly for MaterializeCandidateExported compilation tasks. All state-mutating actions delegate exclusively to buildProposal() $\rightarrow$ substrate.Execute().
• Fail-Closed Nil Guard: Confirmed l.substrate == nil triggers ErrNilSubstrate, enforcing a fail-closed execution boundary.

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Final Build & Verification Matrix

• Go Workspace Compilation: go build ./... $\rightarrow$ Clean (0 errors)

• Architecture Compliance Locks: go test ./internal/architecture/... $\rightarrow$ PASS (2.2s)

• 100% compliance across all 24 Phase Lock tests.

• Substrate Test Suite: go test ./internal/runtime/substrate/... $\rightarrow$ PASS

• Validates FileWrite, FileDelete, Rollback, ReadScope, ExecCmd, and pre-commit AST verification.

• Orchestrator Integration: go test ./pkg/runtime/orchestrator/... $\rightarrow$ PASS

• Linter Status: golangci-lint run ./internal/runtime/substrate/... $\rightarrow$ 0 new issues

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Architectural Invariant Status

• Side-Effect Confinement: Disk mutations (os.WriteFile, os.Remove) and process spawns (exec.Command) are strictly contained inside internal/runtime/substrate/engine.go:242 (Execute()).
• Strategy Purity: All execution modes and strategies emit immutable Proposal structs. Capabilities satisfy:

$$\text{Capabilities}(S) \cap \text{MutationAuthority} = \emptyset$$

• Single Runtime Authority: Single instantiation of NewRuntimeExecutor / NewConcreteSubstrate inside internal/runtime/compose/compose.go, enforcing:

$$\vert{}\text{ProductionRuntimeAuthorities}\vert{} = 1$$